Friday, October 29, 2010
Tree of the Season: The Monterey Pine
The imposing Monterey Pine, Pinus radiata, perhaps the most common large landscape tree in the Bay Area, is one of the most widely-planted trees on the planet. It covers millions of acres in places as far-flung as England, Chile, and Australia. However, its native range covers just a few square miles of the California coastline, which explains why it prefers a cool, moist coastal climate with well-draining soils.
With their dense, towering canopies, dark, glossy green needles, refreshing scent, and magnificent sweep of boughs, Monterey Pines give the feeling of being in a forest. They provide habitat for many species of birds and butterflies. The beauty of these trees, combined with their immense vigor and rapid growth, appeals to landscapers who want a quick, tall screen between houses; a cool shady hillside behind their home; or an instantly woodsy subdivision.
Unfortunately, the quick hedge or woodland effect you enjoy in the first year of the tree’s life can become a major safety hazard and a source of conflict with uphill neighbors when, two decades later, the tree reaches 50-70 feet in height. The Monterey Pine’s soft, brittle wood and its shallow root system combine to make it a serious hazard during winter storms on the hilly slopes. Away from its native habitat, it is vulnerable to root-rot diseases and, stressed by lack of water during our dry summers, it becomes prey to often fatal beetle infestations. The species is relatively short-lived–-around 75 years––and its proclivity for toppling, or for shedding large branches, increases with age.
So what are we to do with these beautiful but bothersome pines that define so much of the Bay Area landscape? First of all, don’t plant any more of them unless you are willing and able to offer them ideal conditions. These include a large, level, adequately moist planting site, with porous soil, far from both houses and power lines, and with no uphill neighbors whose views your growing tree will obstruct. Monterey Pines also require regular care, including safety thinning every few years, as well as periodic watering, aerating, and fertilizing.
If you are already living with Monterey Pines, reduce the safety risks through preventative maintenance before it’s too late. To improve drainage, invigorate your pine’s root system, and strengthen its resistance, we suggest aerating, then filling the holes with rich, porous organic matter (we use American Soil’s “Clodbuster” mix). Check your pine for infestations by looking for areas where whole branches are turning brown, as well as for small holes, tubes or splotches of pitch, or red “sawdust” droppings around the trunk and major branches.
The best time to prune any type of pine trees, and the only recommended time to prune Monterey pines, is between October 1 and February 15. Sap from pruning cuts attracts beetles destructive to pines. These beetles are dormant during the fall and winter months. Given that the beetles can smell sap from long distances, it is important to prune your pine when they are inactive. Not only are the beetles themselves harmful, but some species can carry pine pitch canker, a fungal disease that disfigures pine trees and sometimes kills them. If your tree has dead tips scattered throughout the canopy it probably has pine pitch canker. If you want to prolong the life of the tree, as well as its appearance, now is the best time to prune out the diseased tips.
Even healthy pines require occasional pruning to keep them safe and beautiful. To reduce the fire hazard associated with pines, fire departments recommend removing deadwood and taking branches back from buildings. Pines are sometimes subject to branch and column failure. Judicious thinning of the crown reduces the wind-sail effect of the canopy and thereby reduces the risk of the tree falling in a windstorm. Removing weight from the ends of heavy branches reduces the likelihood that those branches will break.
The safety pruning of trees is an art as well as a science. A well-pruned tree should not only be safer, it should look beautiful. At Brende and Lamb, we take great pride in both the science and the art of pruning. Now is the best time to make your pines as safe, healthy, and beautiful as possible.
If your trees and shrubs need a little TLC - call us to schedule a free estimate.
Blaine Brende & Joe Lamb